Liquid containers such as those of electric accumulators



LIQUID connnmn sudn AS THOSE OF ELECTRIC ACCUMULATORS Aug. 27, 1946. B. L. DAVIES Filed May 25, 1943 91pm Mil ER Patented Aug. 27, 1946 LIQUID CONTAINERS SUCH AS THOSEOF ELEGTRI G ACCUMULATORS:

Eeniamih Lionei Davies, Littfefiever, nearBoIton; England; assignor to Unitedilfibonitej Lorival Limited, Little Lever, near Bolton, Engfand a;

British company Application May 25,? 1943, Serial: No. {88,422 In Great Britain January 5, I942 Claims"; l

invention relates to containers for corrosi've liquids, such as" fixed and. portable acid vessels, including those of electric accumulators, and. has for its obiect' the provision of. an improved construction of container such that loss of liquid or electrolyte resulting. froni shock.- damage may be minimised or obviated; also to provide an improved method" of producing suona container. v

Containers for corrosive liquids are commonly. made of hard rubber or eboni'te' (hereinafter termed ebonite for. convenience of reference) and to. obviate loss of liquid. upon sustaining shockdamage, it has beenproposedto provide an outer cover oi soft vul'cani'sed, rubber in. the formiof a liquid-tight bag, which is slipped over the container after manufacture. To avoid sagging, the method. invofves the stretching of the rubber bag to a limited extent which accelerates ageing of vulcanised. rubber; When ribs, pads or other spacing devices are providedonthe exterior ofthe walls 013 thecontainer in order thataventilation space shall exist between adjacent containers, the rubber bag detracts i romneatnessand is disadvantageous inasmuch: as the ventilationis obstructed.

It has also been proposed. to provide a rubber bag which-is separately vulcanised and fitted into the container after manufacture,-.thus acting. as a lining... In this proposali the rubber is not" stretched and does: not obstruct ventilation butis difficult to: manufacture with adequate dimen sional accuracy. It is also noteasy to fit such a;

bag. into position in a'relatively large deep container. Furthermorethe upperedges of the bag must be anchored: to avoid sagging. and this involves difliculty. We have found the protectionprovided by this device to be good.

A further proposal is to construct-the:- container witha rubber lining built integrally with thewalls, the whole being vulcanised together..- In the finished container the rubber liningv fits perfectly and is firmly attached to the ebonite walls over the'whole of their area-.1 Such' a lining gives some protection against: loss; or liquid when? sub mitted-toshock but itliasbeen-found: that where: cracking of the ebonite occurs giving rise to sharn or jagged edges the rubber lining tends to be cut or torn.

Rubber-lined accumulator containers in which the rubber adheres tightly to the hard rubber or ebonite are not satisfactory, for cracking of the ebonite involves tearing or cutting of the rubber.

On the other hand if the rubber lining is clear of in est 2.

container, the" air'trapped between the lining and the ebonite causes defects which are not wholly eliminated by venting the air space.

The invention comprises the provision or'a filiing or int'rply between the" Hiring and the ebcnite which eii'ects'during manuf cture a joint'betweri the parts so that air is wholly or sutstantiaiiy excluded: from between them but which does not join them together. in the; finished viiioanised article or jbins them so weakly" that the force required to. part them is'muchle's's' than that re quired to break the eboni'te so that the containei is subjected to shock, which may cause the ebonite to cracl'g, the lining which remains soft after vulcanisati'on acts as if it were loose and unattached. to the" eboni'te.

The invention further comprises anchoring the ebonite to the lining at. the open endof the container or at an opening or branch upon the ontainer by omitting the filling or interply between thelining. and ebonite at. such part or parts.

The invention further comprises the method of producing alined ebonite. container in which; acore orformer of external shape corresponding. totheinterior ofthe container is covered: with a thin layer (which may be multi-plyl oi vulcanisablesoft rubber. mixture which is then covered partly or completely by a layer or layers of paper coated, though not: impregnated-,. with rubber solution. or a solution. ot a vulcanisablerubber mix, and dried the walls or the container which are made wholly or substantially or a vulcanisable eboni-te mixture being then built upon the paper coveringthe: wholebeing. rolled firmly together and then subjectedto vulcanisation; which leaves the outer walls hard, the lineing. soft: and; the paper tendered, weakened. or partially disintegrated The invention: turther. comprises the methods in. which the' paper covering is shorter than thedesired depth or the container so that thelining and walls of the container may come together and belbond ed togetherin a limited area near the open end: of the container.

The invention further comprises th method: in which-.therpaper covering is emitted at flanges so that the lining and walls areb'onded-together thereat.

The invention further comprises containers whenever produced by the methods described.

Referring to the accompanying sheet of explanatory drawings:

Figures 1 and 2 are sectional views of parts the ebonite which is particularly the case when of lined vessels illustrating the method of pro- 3 ducing the same in accordance with thi invention.

Figure 3 is a sectional view showing how a branch connection on a vessel is produced in accordance "with this invention.

Figure 4 is a sectional elevation of part of a tube or pipe produced in accordance with my invention.

A core or former a is shown in Figure 1 which is formed of steel or cast iron and which, after the formation of the container, is removed therefrom. The core or former corresponds in external shape to the internal shape of the container to be produced and is covered with a thin layer b of vulcanisable soft rubber mixture, preferably made of two plies. This is then covered partially or completely b a layer or layers of paper propriate crossesection which has or have been previously coated on both v thefwhole being rolled firmly together in order to effect complete or substantially complete exclusion of air from between'the various layers which will form th finished container. The structure is now subjected to vulcanisation, preferably in steam, which leaves the lining b soft, the outer walls d hard, and the paper 0 tendered, weakened or partially disintegrated. It follows, therefore, that thereis substantially no'joint made between the lining and ebonite, except at e where the lining b was not covered by paper. Th core or former is of course removed when the container has been formed thereon.

The lining may consist of a rubber composition which remains soft after vulcanisation or of a rubber-lik synthetic substance which remains soft after vulcanisation or of a non-vulcanisable plastic material which can be rolled into and retains the form of thin sheets which show a tendency to adhere to ebonite. During manufacture of the container the interpl adheres to the lining and to the ebonite but such adhesion is substantially destroyed during vulcanisation.

The intermediate layer c'may consist of paper or other material of like form, provided it does noteifect a bonding of the lining b and ebonite d after vulcanisation has been effected. When the lining is of non-rubber substance, one face of th interply is coated with a solution of that substance or a related substance to effect a joint to the lining, and the other face of the interply is coated with rubber solution to eifect a joint with the unvulcanised ebonite composition (1. In the case where more than one layer of intermediate material 0 is employed one layer may be adherent to the lining b and another to the ebonite d after vulcanisation. The layers of c are adherent to one another before vulcanisation but must leave the lining b non-adherent thereto after vulcanisation.

Figure 2 shows a section of part of an electric accumulator cell container. In this instance the upper edge of the lining b which remains soft after vulcanization is protected by first applying a strip 1 of ebonite stock to the core a, lightly attaching it b means of rubber solution. The rests or ribs 9 in the base of the container are next formed by placing strips of ebonite stock of apinto grooves formed in the base of the core a. The lining b which may be of polymerized butadiene is next built on .to the core at, its upper edge being bevelled as indicated at is to suit the ebonite strip The interply c of Cellophane or paper is then applied and finally the material to produce the ebonite walls at as before. After vulcanisation the strips ,7 become integral with th container wall d. Such strips 1 which are hard protect the upper edge of the lining b which remains soft.

Figure 3 shows the application of our invention to the outlet of an acid storage vessel. The container is built up as before by incorporating the paper interply c. The soft rubber lining b is caused to adhere to the face h of the outlet boss, thus forming a sealing layer for a flanged fitting to be attached.

Figur 4 shows part of a liquid container of tubular form made in accordance with the present invention. The ebonite tube 03 is built as before on a cylindrical core, and there being a soft rubber lining b with paper interply c, the latter being cut shorter than the lining so that a soft rubber facing is provided which is permanently attached to the flanges as 2'.

With my improvement, where the lining b does not adhere to the ebonite d, if the latter is frac tured by a violent blow, I have found that the lining b is free to stretch over a considerable area on each side of the fractur and therefor does container in which a core of external shape corresponding to the interior of the container is covered with a thin layer of vulcanisable soft rubber mixture which is then covered by a layer or layers of paper coated, though not impregnated, with a solution of a vulcanisable rubber mix, and dried, the walls of the container which are made of a vulcanisable ebonite mixture being then built upon the paper covering, th whole being rolled firmly together'and then subjected to vulcanisation which leaves the outer walls hard, the lining soft and the paper partially disintegrated.

2. The method of claim 1 in which the paper covering is shorter than the desired depth of the container so that th lining and walls of the container may come together and be bonded together during vulcanization in a limited area near the open end of the container.

3. The method of claim 1 in which the paper covering is omitted at flanges so that the lining and walls are bonded together thereat during vulcanization.

. BENJAMIN LIONEL DAVIES. 

